Vertical-lift bridge.



T. RALL.

VERTICAL LIFT BRIDGE.

APPLICATION FILED MAY 19. 1913.

' 1 14%,3 1 $0 Patenteoi May 18, 1915.

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VERTICAL LIFT BR|DGE. APPLICATION FILED MAY 19. 1913.

LMQEI 6o Patented May 18, 1915.

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WETIGAL-LIFT Specification of Letters fieatent.

Patented May id, 3915..

Application filed Hay 19, 1918. Serial EQ 0. 768,551.

ToaZZ whom it may concern Be it known that T, Tnnonon BALL, a citizen ofthe UnitedStates, residing at Chicage, in the county of Cook and Stateof Illinois, have invented certain new and useful Tmprovements inVertical-Lift Bridges, of which the following is a specification.

My invention relates in general to movable bridges, and moreparticularly to vertically lifting bridge spans.

The primary object of my invention is to provide a -vertically movablebridge span with simple, eiiicient means for counterbalancing the weightof the span and compensating for the expansion and contraction of thespan, due to changes in temperature.

A further object of my invention is to provide a vertical lift bridgewhich will be simple in construction, efhcient in operation, andconvenient in use. My invention will be more fully disclosed hereinafterwith reference to the; accompanying drawings, in which the same isillustrated as embodied in several convenient practical forms, and inwhich- Figure l is a side elevational view; Fig. 2 a plan view of theembodiment of the invention shown in Fig. 1; Fig. 3 a view similar toFig. 1, showing a modified form of my invention; and Fig. 4 a viewsimilar to Fig. 1 showing still tion.

Similar reference characters are used to designate similar parts in theseveral figures of the drawings.

Reference letters A and B designate stationary approach spans, betweenwhich is located a vertically movable span E. The approach and movablespans may be of any suitable construction, such, for instance, astrussed bridge spans.

C, D designate piers upon which the ends of the stationary spans A andB, respectively, are permanently supported, and upon which the ends ofthe movable span Fl normally rest.

G and H designate levers in the form of trussed girders, which arepivotally fulcrumed at g and h, respectively, upon tower posts N and Umounted directly-upon the piers C and D and secured to the adjacentstationary spans A. and B. Each of the lovers G and ll is provided witha weight to counterbalance the weight of the vertically movable span.The end of each of these levers, opposite to the end on which anotherform'of my haven-- the counterbalance K is mounted, is provided with aroller L, which engages beneath a track M fixed to the upper chord F ofthe vertically movable span.

it will be understood by reference to Fig. 2 that the lifting levers Gand i land the parts coiiperating with themyare arranged in pairs, onepair being located at each end of the movable bridge span.

Any suitable mechanism may be provided for raising and lowering the spanE, such mechanism being shown as comprisin a longitudinal shaft Pjournaled upon the lift ing-span E and provided with pinions ffixed toits opposite ends, which mesh with racks 71. secured to the verticalposts N and 0. Any suitable arrangement of shafts and gears may beprovided for rotating the shaft P, such, for instance, as a verticalshaft Q mounted upon the movable span E and operatively connected at oneend by meshed bevel gears q with the shaft P, and its other end bymeshed bevel gears r with a power shaft R, which may be rotated by anysuitable motive power, I such, for instance, as electricity or steam, orby hand.

The operation of my improved lifting bridge, as illustrated in Figs. 1and 2, is as follows: When it is desired to lift the span' E, theshaft Pis rotated, which causes the pinions p, through engagement with thefixed racks n, to travel upwardly thereby raising the span E between theposts N and (l. The weights K on the outer ends of the lifting levers Gand H counterbalance the weight of the span Fl during its verticalmovement. During the upward movement of the span the supporting rollersill have paths of movement in the arcs indicated in dotted lines inFig. 1. owing to the lifting levers being pivoted at g and h,respectively, upon the tower posts. During the lifting of the movablespan the rollers L on the inner ends of the levers roll inwardly alongthe tracks M until the rollers lie in the horizontal plane of thefulcrums g and h of the lifting levers, and during the remaining liftingof the span the rollers move outwardly relatively to the tracks M, whichthey engage, and through which they transmit the lifting power oi thelevers. In order to lower the span it is merely necessary to reverse thedirection of rotation of the shaft P.

Tn the form of my invention illustrated in Figs. 1 and 2, the horizontaldistance between the fulcrum of each lifting lever and by providing thelevers with rolhng fu'l- I terbalancing wei ht while its inner en isivotallv connected at crums. acters A and B esignate stationary towerposts at the op osite ends of the vertically movable sp'an' such towerposts being mounted upon the piers C and D, respectively. G and Hdesignate thelifting le vers, each of which is rovided witha counat ,itsouter end,

L to the upper chor F of the an E. The fulcruins of the levers G andconsist of rollers g and h, respectively, which rest upon tracks a and bon the tops of the tower posts A and B. raising and lowering the span inthe form ofmy inventionshown in Fig. 3 may be the same as abovedescribed in connection with Figs. 1 and 2, or any other suitablelifting mechanismmay be provided.

In the operation of the embodiment of my invention shown in Fig. 3 thefulcrums g and h of the lifting levers G and Hi roll outwardly until thepivotal connections L of the liftin levers with the top chord of thespan reac the horizontal plane of the fulcrums, after which the fulcrumsroll inwardly, or toward each other, during the remaining liftingmovement of the span.

In Fig. 4 I have illustrated still another embodiment of my invention,in which the pivotal movement of the lifting levers during the verticalmovement of the span is compensated by providing merely one of thelevers with a rolling fulcrum. In this figure reference characters A andB designate the tower posts mounted upon piers C and D, respectively. IEdesignates the lifting span, which normally rests at its ends upon theadjacent piers. G and H designate the lifting levers, each of which isprovided at its end with a weight K for counterbalancing the span. Theinner end of each of the lifting levers is pivotally connected at L tothe upper chord F of the span E The lever G is pivotally fulcrumed at 9upon the top of the tower A, while the lever H is provided with arolling fulcrum k which rests upon the track b at the top of the towerB.

In the operation of the embodiment of m invention shown in Fig. 4, durinthe-lifting of the span the fulcrum h o the lever Referrin to Fig. 3,reference char- The means for H shifts outwardly along the track 6 untilthe pivotal connections L of the lifting levers with the up er chord ofthe span reach tlnrhorizontal p ane of the fulcrum. of the levers afterwhich'the fulcrum k of the lever I-I rolls inwardly durin the remaininglifting of the span. It wi be observed, by reference to Fig. 4, that inthe form of my invention shown therein, the ends of the bridge are movedin arcs indicated in dotted lines, when the bridge israised or lowered.

In the several forms of my invention herein illustrated and described,not only is the pivotal movement of the lifting levers during the raisin.and lowering of the span compensated for, ut the expansion andcontraction of the span is also compensated for through the shiftingeither between the vers and the span or between the levers and the towerposts upon which they are fulcrumed.

From the foregoing description it will be observed that I have inventedan improved lifting bridge which may be vertically raised or lowered bymeans of piv otal levers, the pivotal movement of the levers during thevertical movement of the bridge span being compensated by means forvarylng the horizontal distance between the fulcrum points of the leversand the pivconnections provided otal connections of the levers with thespan. It will also be observed that in my improved mechanism for liftingbrid spans the expansion and contraction o the span is so compensated asto in no wise ail'ectnthe efficient operation thereof.

1. In a bridge of the classdescribed, the combination with a'verticallymovable span, of stationary supports at each end of said span, andcounterbalance levers pivotally mounted upon said supports and pivotallyconnected directly with the opposite ends of said span, the pivotalconnectipns of one of said levers comprising one fixed'pivot and onepivot in freely movable engagement with a substantially horizontal trackfor automatically varying the horizontal distance between the fulcrumpoint of said lever and its point of pivotal connection with theadjacent end of the span to compensate for the pivotal movementofsaidlever during the vertical movement of said span.

2. In a bridge of the class desc -'ibe(l, the

combination with avertically movable span,

of stationary supports at each end of said span, and counterbalancelevers pivotally mounted upon said supports and pivotally connecteddirectly with the opposite ends of said span, and the, pivotalconnections of each of said levers comprising one fixed pivot and i onepivot in freely movable engagement with a substantially horizontal trackfor automatically varying the horizontal disincome tance between thefulcrum oint of eachlever and its pivotal connectlon with the adjacentend of the span to compensate for the pivotal movement of the leversduring the vertical movement of the span.

3. ln abridge of the class described, the combination with a verticallymovable span, oi stationary supports at each'end of said span,counterbalance levers pivotally mount-- ed upon said supports, and meansfor pivotally connecting said levers directly with the opposite-ends ofsaid span, the means for pivotally connectin one of said levers with theadjacent end 0% the span consisting of a pivot in freely movableengagement with a, substantially horizontal track to compensate for thepivotal movement 013 said lever during the vertical movement of the spam4C. lln a bridge of the class described, the combination with avertically movable span, of stationary supports at each end of saidspan, counterbalance levers pivotally mounted upon said supports,substantially horizontal tracks upon the opposite ends of said span, andpivots on the ends oil said levers in freely movable en agement withsaid substantially horizonta tracks, the point of pivotal connectionbetween each of said levers and the adjacent end ol the movable span tocompensate for the pivotal movement of said levers during the verticalmovement of the span.

5. in a bridge of the class described, the combination with a verticallymovable span, of stationary supports at each end of said span,counterbalance levers pivotally mounted upon said supports and pivotallyconnected with the opposite ends of said span, the pivotal connectionbetween the end of one of said levers and the adjacent end of said spancomprising a rolling bearing and a member engaged thereby whereby thehorizontal distance between the fulcrum point of said lever and itsconnection with the span will automatically vary during the verticalmovement or the span to compensate for the pivotal movement of saidlever.

8. ln abridge of the class described, the combination with a verticallymovable span, of stationary supports at each end of said span,counterbalance levers pivotally mounted upon said supports and pivotallyconnected with the o posite ends or? said s an,

the pivotal connection between the en of each of said levers and theadjacent end of said span comprising a rolling bearing and a memberengaged thereby, whereby the horizontal distance between the in c waspointspl the levers and their connection with the span willautomatically vary during the vertical movement of the span tocompensate for the pivotal movement of said levers.

7. In a bridge of the class described, the combination with a verticallymovable span, of stationary supports at each end of said span,counterbalance levers pivotally mountvertical movement at the span tocompensate "for the ivotal movement ofsaid lever.

8. In a bridge or? theclass described, the combination with: avertically movable span, of stationary supports at each end of saidspan, counterbalance leverspivotally mount- 1 ed upon said supports anpivotally connected with the opposite ends of said span the pivotalconnection between theen oil each of said levers and the adjacent end ofthe span comprising a track fixed to the span and-a roller on the end ofthe lever engaging the track, whereby the horizontal distance betweenthe fulcr points of said levers and their connections with the span willautotically vary during the vertical movement of the span to compensatefor the pivotal movement of said levers.

9. lln a bridge of the class described, the combination with avertically movable span, of stationary supports at each end of saidspan, counterbalance levers ivotally moun ed upon said supports anpivotally connected with the opposite ends of said span, the pivotalconnections of one of said levers comprising one fixed pivot and onepivot in freely movable engagement with. a substantially horizontaltraclr for compensating for the expansion and contraction of said span.

lln testimony whereof, ll have-subscribed my name.

THEUDUR -RALL.

Witnesses @139. lb. Wmnrnson, lrllnnnv n. Penn's.

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